One Romantic Night is a 1930 American pre-Code romantic comedy film directed by Paul L. Stein. It is the first sound film version of Ferenc Molnár's play The Swan, and marked silent screen star Lillian Gish's talkie debut. She starred as Princess Alexandra, with Conrad Nagel as the tutor who falls in love with her, and Rod La Rocque as Crown Prince Albert. In this version, Alexandra and the Prince elope at the end. The film was only fairly successful, though Gish would go on to become as highly regarded in talking pictures as she had been in silent films.

A silent version of the play had been produced in 1925 at Paramount Pictures. The 1956 Eastmancolor film version of The Swan, the only one of the three film versions made in color, is much more frequently shown today.